Method and system for recovering shale oil and gas



Jan. 9, 1.968 w, T|NL|N I 3,362,751

METHOD AND SYSTEM FOR RECOVERING SHALE OIL AND GAS Filed Feb. 28, 1966Ihn l PART B Unitecl States atent 3,362,751 METHOD AND SYSTEM FORRECOVERING SHALE GIL AND GAS William Tinlin, 21 Hickory St., ChicagoHeights, Ill. 60411 Filed Feb. 28, 1966, Ser. No. 530,423 6 claims. (er.299-4) This invention relates to a method ofrecovering shale oil 'andgas from shale oil formations through the application of heat undercontrolled conditions wherein both the hydrocarbon liquids and vaporsare recovered. The invention depends in part upon the excavation of acertain configuration or system of tunnels and galleries havingprescribed slopes or elevations in -relation yto each other incombination with heat lconveying means, valve means and condenser meanswhereby substantially 'all hydrocarbon liquids and vapors freed by theheat are recovered.

Attention has I'been direction for sometime ito the recovery ofhydrocarbon loil from shale formations by various methods. One approachinvolves mining the shale, crushing the large aggregate and subjectingthe comminute'd shale to retorting in furnaces of various designs andcapacities. The necessity of handling the shale adds greatly to thecost. -In situ treatment of shale has been -practiced but has notattracted too much attention because of costs informing tunnels,inefficiency in the application of heat and the apparent necessity ofusing radditional expedients, such as lpressure, complex |tunnel andshaft systems and extreme direct heat or combustion of the shale strataitself tto obtain the desired Irecovery. The prior art processes havenot become practical because of the high costs due to least in part tothese yfactors. 1n addition little attention has been directed torecovery of the vapors that result from the in situ application of heatto a shale oil formation.

Now in accordance with this invention these diiculties are overcome bythe provision of a method which is characterized lby the use of a simpletunnel and shaft system with tunnels and `galleries having certainslopes and elevations, along with the use of heat conveying and recoverymeans and provision for the continuous how recovery yof substantially`all of the oil and vapors as such or in the form of additional heat forthe process. The process of this invention is also characterized in one`aspect iby `control of the air passing into the :tunnels wherein heat-is being applied to the shale in such a manner as to allo-w completeheat utilization through the application of heat lunder controlledconditions within a system of convecting tunnels and shafts.

Ilt becomes a primary object of this invention to provide a method ofrecovering oil from shale oil formations in situ.

Another object of this invention is -to provide a system of simplevalve-controlled tunnels, shafts and galleries within 1a shale formationto provide for heat circulation and recovery along with condensers andoil sumps in a particular combination for emcient shale oil recovery.

Another object of this invention is ythe provision of an interrelatedsystem of converging heating and return tunnels, vertical vapor shaftsand interconnecting galleries with cooperating condenser and sumps,whereby heat applied Ito the shale 'formation passes upwardly andinwardly therethrough a manner t drive out oil and vapors into theheating Itunnel or tunnels toward at least one vapor shaft whereby IVtheoil descends -to a gallery and return tunnel for recovery, and vaporsare allowed to ascend the cooler walls for partial condensation andreturn to the gallery and return tunnel and any uncondensed vapors aretrapped in `a condenser at the `top orf the shaft for separate recoveryor return thereto.

Another object of this invention is to provide a methice od of in situoil and gas recovery from an exposed shale formation wh-ich includes`the steps of 1) 'forming at least a pair of lconverging spaced upperand lower tunnels in a vertical face of the exposed shale formation, (2)forming an interconnected gallery between 'the lower tunnels, (3)forming at least one vertical `shaft extending from an upper portion ofthe shale formation and communicating with the `tunnels and gallery,applying heat to the Iformation through the tunnels from an exrternal,high temperature, heat `source and recovering oil and condensate |bydirect dlow from the lower tunnel.

The invention has as one feature the placement of at least one pair oftunnels one above the other such that the top tunnel is slopeddownwardly into the formation and the bott-om tunnel is opposite, thatis, slopes upwardly into the formation. `By connecting the ,upper and-lower 'tunnels with a vertical shaft, and applying heat to the -tunnelsystem an effective in situ shale oil recovery system is provided.

A yfeature of this invention is that ithe application of hightemperature heat to the shale for-mation in the vicinity of the tunnelscauses the lflow of oil and vapors therefrom, the former Ibeing directedby the downward slope of lthe upper tunnel to a vertical vapor shaft andthence ito `a lower gallery and through the oppositely sloped returntunnel to a sump for recovery or use, and the latter being `directed ltosaid vertical vapor shaft and by the stack effect Itherein to suitablecondensing means for recovery.

Another feature of this invention is the provision of air control lockson the inlet ends of said heating and return tunnels whereby the ow ofconvection air through said system is controlled for maximum heatutilization and oil recovery.

These and other objects of this invention will become apparent or bedescribed as the specification proceeds.

This invention may be illustrated by various embodiments including thoseillustrated by the drawings wherein:

FIG. 1 is a diagrammatic illustration of the vertical face of an exposedshale formation showing two forms (Parts A and B) of tunnel, recoveryand heating systems; and

FIG. 2 is a cross-sectional view also in diagrammatic form taken alonglines 2-2 (Part A) of FIG. 1.

FIGS. 1 and 2 show diagrammatically a shale formation 10 with cliff face12 as it may appear after removal or stripping of surface material toexpose same for treatment. Referring to FIG. 2, tunnels 14 and 16 aredrilled` into the face of the shale formation to a depth of about 50 to100 feet. Tunnel 14 is sloped downwardly into the formation. The amountof slope is not as important as the presence of sufl'icient slope tocause any liquid oil therein to flow freely inward under the influenceof gravity. Similarly tunnel 16 is cut or drilled at a lower elevationinto the face 12 at a slight upward slope, again for the purpose of freegravitational outward flow therein. Tunnels 14 and 16 are cut atdifferent elevations into the face 12, that is tunnel 14 is about 30 to50 feet above tunnel 16. A shaft 1S is drilled into the top of the shaleformation 10 to intersect tunnel 14 and terminate at tunnel 16. In thesimplest form this invention can be practiced with only two tunnels 14and 16 in combination with a single shaft 18 as will hereinafter beexplained. The tunnel and shaft system shown is made possible by moderncontinuous drilling equipment such as that shown in my Patent#3,005,627, or that disclosed in my copending applications Ser. Nos.360,555, filed Apr. 1, 1964, now U.S. Patent No. 3,314,724, and 392,484,iiled Aug. 27, 1964, now U.S. Patent No. 3,314,725.

At the top of shaft 18 there is provided condenser 20 which may be ofany suitable type designed and controlled to provide suicient cooling tocondense the hydrocar- 3 bon vapors, except the noncondensible gases,issuing from shaft 18. Flue 22 is provided to collect and convey anyuncondensibles for separate recovery or use.

Heat source 24 is located on valley floor 26, preferably a few feetbelow tunnel 16, i.e. 2 to 6 feet, and may cornprise any means forsupplying heat to the shale oil formation. Heat source 24 may produceheat in the form of hot gases, or liquids and preferably in the form ofsuperheated stream at a temperature of about 800 degrees F. to 1600degrees F. With a three stage heater, for example, a temperature as highas 1800 degrees F. can be attained. The heat carrying medium from heatsource 24 is conveyed through conduit 28 which extends through tunnel 14and then, via leg 311 and return line 32 passing through tunnel 16, backto heat source 24.

The open end of tunnel 14 is provided with a valve means indicated at 34which may comprise any means for opening and closing the entrance totunnel 14 in a manner so that control of the air flow thereinto isattained. To illustrate a frame member 36 is provided Within Which asliding door member 38 operates to attain the desired graduated openingand closing thereof. A similar valve means 4d is illustrated in relationto the open end of tunnel 16 by means of frame 42 and sliding door 44.Other equivalent valve means than a sliding door arrangement can beused.

ln order that liquid oil in tunnel 16 is collected there is provided atrough means 46 and sump 48 which later is shown as a sunken tank.Conduit 50 connects between sump 48 and heat source 24 for the purposeof providing a source of fuel for heater 24 Where same is an oil burningfurnace.

Tunnels 14 and 16 may be provided with a suitable shoring, not shown, toprevent collapse as the removal of liquids `and gases proceeds withinthe shale formation surrounding tunnel 14. Galleries connecting thejunctures of a series of the tunnels and shafts, one to the other areshown at 54 and 56 (see FIG. l).

In one aspect of this invention one pair of tunnels 14 and 16 can beused with one shaft 1S and one heat source 24. However, in a preferredembodiment one heat source is used with a plurality of tunnels asillustrated in FIG. l wherein corresponding parts to FIG. 2 bear theSame numerals.

In addition, FIG. l shows that the shafts 18 and 18 may be substantiallyvertical With tunnels 14 (and 14') and 16 (and 16') being similarlyaligned (Part A) or may be (as shown in Part B) arranged so that shafts18 and 18 converge downwardly or are not vertical and tunnels 14 and 14'and 16 and 16 are likewise arranged. In each instance, the tunnelsintersect with the shafts at the point of intersection with thegalleries 54 and 56.

In order to illustrate this invention the following examples are given:

EXAMPLE I T wo tunnels and one shaft After exposure of shale formationand cliff face 12 by removal of surface rock and other covering, tunnels14 and 16 are drilled therein using a boring machine which cuts a holeabout six feet in diameter. When necessary, suitable shoring means isinstalled in tunnel 14 las the bore progresses. Shaft 18 is then drilledfrom the top of the clil to connect the ends of tunnels 14 and 16.Tunnel 14 is cut so that it slopes into the shale formation at the rateof about 1 to 2 inches per foot. Tunnel 16 is cut so that it slopes inthe opposite direction, that is, out of the shale formation, and atabout the same slope as tunnel 14. With this size tunnel and shaft thereis no difliculty in the installation of heat conduit 28 therein andconnected back to heat source 24, which may be a three stage furnacecapable of producing super heated steam at 800 degrees F. to 1600degrees F. and as high as 1800 degrees F. Condenser is installed andvalve members 34 and 40 are attached over an open ends of tunnels 14 and16. Trough 46, and sump 4S are installed to provide gravity A flow ofoil from tunnel 15. Line 'S0 is connected to sump 4S for auxiliary fuel.

Heat in the form of super-heated steam at about 1200 F. is sent throughconduit 28 and valves 34 and 40 are closed. As the heat permeates theshale formation, oil begins to dow therefrom and gravitate into tunnel14. The backward slope thereof causes this collected oil to ow intoshaft 1S, downward into tunnel 16 and out tunnel 16 to sump 48. Tohasten the initial heating, valve 34 is closed and valve 40 is opened.As the heating continues, vapors of lower boiling hydrocarbons anduncondensible gas C1 and C3 are collected in shaft 18 and rise tocondenser 20 for recovery. Any uncondensible gases are conveyed to asuitable separate recovery system (not shown) by means of olf-gas flue22. Gradual removal of vapors from the system is controlled so thatthere is substantially no dow of air into tunnel 16 via valve 40. Asremoval of oil from the formation lil continues, valve 40 is graduallyclosed and valve 34 gradually opened to allow more air to enter tunnel14. This carries heat from conduit 28 and the surrounding partiallydenuded shale further into the formation and increases over-allrecovery. The temperature in the shale will reach about 1000o F. Controlof air intake from this point on to maximize the transfer of heat to theshale formation is accomplished by the operation of condenser 20 and ue22 and manipulation of the values 34 and 40. Finally, the shale aroundand above tunnel 14 is denuded of oil and begins to crumble andcavitate. Valve 34 can be fully closed to drive the heat from thecavities and crumbled shale into the formation still further. The pocketof denuded shale so created may also be removed to recover the conduit28 and to expose a new cliff face and the process steps repeated.

EXAMPLE H Four tunnels, two sltczfts and one or more galleries The stepsof Example I are repeated and each pair of tunnels is connected at itsrearward end with a shaft and a substantially horizontal gallery` Asheat is applied, this time in the form of a molten metal, the valves areoperated in the same manner as in Example I to control by naturalconvection the flow of air through tunnels 14 and 14 so as to transferthe heat to the surrounding shale body. The temperature of the shale mayrise to about 1800 degrees F. In using a molten metal as the heatingmedium care lmust be taken not to allow too great a rate of heattransfer on the one hand and freeze-up in the conduit on the other. Oilpasses into tunnels 14 and 14', drains into gallery 56 and thencethrough tunnels 16 and 16 into sump 48.

EXAMPLE III A plurality of tunnels, shafts and galleries The steps ofExample II are continued by drilling a plurality of tunnels 14 and 14into the face of a shale cliff. Interconnecting vertical and slantingshafts are sunk to connect with the extended ends of the tunnels. Theinterconnecting galleries `are drilled. The conduits, condensers,valves, perforated pipe, heat sources and sumps are installed. Heat isapplied to the shale formation for about two days over about 1500 linearfeet of cliff face 50 feet high. lOil is continuously recovered in thesumps and condensate from the condensers. At the end of this time theconduits are removed and a fresh cliff face exposed by removal ofdenuded shale.

From the foregoing examples and description, it is apparent that theprocess of this invention has several unforeseen advantages. First, theprovision of the control of the `air flow helps to retain the heat inthe upper tunnel for a sullicient time to drive the heat into theformation by natural convection and aids in regulating the conveyance ofoil and vapors from the top tunnels. Secondly, the withdrawal andrecovery of vapors is also in the direction of natural convectionthrough the system which further aids and augments heat utilization andoil recovery. Recovery of the vapors immediately as they form preventsfurther breakdown or cracking and reduces losses due to decomposition.The over-all system mitigates losses and waste of heat and oil andvapors. The rate that oil is taken from any shale hed will be determinedby the heat used, by the number of tunnels and shafts and the control ofthe air allowed to enter the system.

Having thus `described this invention, it should be understood thatdetails thereof may be altered or omitted Without departing from thespirit of the invention as dened by the following claims.

I claim:

1. The method of recovering shale oil and gas from an exposed shaleformation which comprises (a) forming at least one pair of verticallyspaced tunnels into the face of said formation, the uppermost of saidtunnels being inwardly sloped and the lowermost of said tunnels beingoutwardly sloped,

(b) forming an interconnecting shaft between the top of said formationand said tunnels,

(c) passing a heating medium at a temperature sufi-icient to cause theseparation of oils and gases into indirect contact with said shaleformation surrounding said spaced tunnels, said heating medium beingsent rst through said uppermost tunnel, through said vertical shaft andout through said lowermost tunnel, and

(d) recovering liquefied oil from said tunnels and recovering said gasesfrom said shaft.

2. The method according to claim r1 wherein the air entering the saidtunnels is regulated to control the stack eect of said shaft.

3. The method in accordance with claim 1 in which said heating medium ismaintained at a temperature within the range from about l800 F. to-about 1600 F. in the said uppermost tunnel and the air flow enteringsaid upper tunnel is regulated to control the stack effect of saidshaft.

4. The method in accordance with claim 1 in which a plurality of saidtunnels and shafts are formed in said shale formation, interconnectinggalleries are formed between the ends of said tunnels and their pointsof intersection with said shafts, said heating medium is maintained at atemperature sufcient to produce a space temperature of at least about800 F. within the upper of said tunnels, and said vapors are recoveredby condensing the efuent from said shafts.

5. A system for recovering shale oil and gas from a shale oil formationcomprising a pair of vertically spaced tunnels in said formation, ashaft interconnecting said tunnels adjacent their inner ends and openingto the top of said formation, a high temperature heat source, conduitmeans for transmitting heat from said heat source into the upper of saidtunnels, said conduit means leading through said shaft to the lowertunnel and thence returning to said heat source, adjustable gate meansat the entrance to each tunnel for regulating the volume of air enteringthereinto, and means at the top of said shaft for trapping andcondensing vapors and gas issuing therefrom.

6. A system for recovering shale oil and gas from a shale oil formationas defined by claim 5 wherein a series of spaced tunnels and shafts arecreated in said formation to provide a series of pairs of verticallyspaced tunnels each pair having -an interconnected shaft, said conduitmeans leads into each of the upper tunnels, down the respective shaftand out through the respective lower tunnel to return to said heatsource, and wherein a sump means is provided for collecting liqueed oiland vapors owing from the lower tunnels.

References Cited UNITED STATES PATENTS 1,269,747 6/191'8 Rogers 166-39`1,418,097 5/ 1922 Schneiders 299-4 X 1,520,737 12/ 1924 Wright 166--40 X1,660,818 2/1928 Ranney 299--2 1,919,636 7/1933 K-arrick 299-2 2,481,0519/1949' Uren.

2,970,826 2/1961 'VVoodrufIr 166-11 X 2,974,937 3/1961 Kiel 166-39 X3,228,468 1/1966 'Nichols 166-11 X 3,338,306 8/1967 Cook 166-40 STEPHENI. NOVOSAD, Primary Examiner.

1. THE METHOD OF RECOVERING SHALE OIL AND GAS FROM AN EXPOSED SHALEFORMATION WHICH COMPRISES (A) FORMING AT LEAST ONE PAIR OF VERTICALLYSPACED TUNNELS INTO THE FACE OF SAID FORMATION, THE UPPERMOST OF SAIDTUNNELS BEING INWARDLY SLOPED AND THE LOWERMOST OF SAID TUNNELS BEINGOUTWARDLY SLOPED, (B) FORMING AN INTERCONNECTING SHAFT BETWEEN THE TOPOF SAID FORMATION AND SAID TUNNELS, (C) PASSING A HEATING MEDIUM AT ATEMPERATURE SUFFICIENT TO CAUSE THE SEPARATION OF OILS AND GASES INTOINDIRECT CONTACT WITH SAID SHALE FORMATION SURROUNDING SAID SPACEDTUNNELS, SAID HEATING MEDIUM BEING SENT FIRST THROUGH SAID UPPERMOSTTUNNEL, THROUGH SAID VERTICAL SHAFT AND OUT THROUGH SAID LOWERMOSTTUNNEL, AND (D) RECOVERING LIQUEFIED OIL FROM SAID TUNNELS ANDRECOVERING SAID GASES FROM SAID SHAFT.
 5. A SYSTEM FOR RECOVERING SHALEOIL AND GAS FROM A SHALE OIL FORMATION COMPRISING A PAIR OF VERTICALLYSPACED TUNNELS IN SAID FORMATION, A SHAFT INTERCONNECTING SAID TUNNELSADJACENT THEIR INNER ENDS AND OPENING TO THE TOP OF SAID FORMATION, AHIGH TEMPERATURE HEAT SOURCE, CONDUIT MEANS FOR TRANSMITTING HEAT FROMSAID HEAT SOURCE INTO THE UPPER OF SAID TUNNELS, SAID CONDUIT MEANSLEADING THROUGH SAID SHAFT TO THE LOWER TUNNEL AND THENCE RETURNING TOSAID HEAT SOURCE, ADJUSTABLE GATE MEANS AT THE ENTRANCE TO EACH TUNNELFOR REGULATING THE VOLUME OF AIR ENTERING THEREINTO, AND MEANS AT THETOP OF SAID SHAFT FOR TRAPPING AND CONDENSING VAPORS AND GAS ISSUINGTHEREFROM.